SOLUTION: Solve by completing the square. 2x^2 + 8x + 5 = 0 If anyone could offer assistance on how to complete this problem step-by-step, it would be greatly appreciated. Thank

Algebra ->  Quadratic Equations and Parabolas -> SOLUTION: Solve by completing the square. 2x^2 + 8x + 5 = 0 If anyone could offer assistance on how to complete this problem step-by-step, it would be greatly appreciated. Thank       Log On


   

Question 89118: Solve by completing the square.
2x^2 + 8x + 5 = 0
If anyone could offer assistance on how to complete this problem step-by-step, it would be greatly appreciated.
Thank you in advance for your time.

Answer by tutor_paul(519) About Me  (Show Source):
You can put this solution on YOUR website!
2x%5E2%2B8x%2B5=0
First, put the x^2 and x terms alone on one side of the equation:
2x%5E2%2B8x=-5
You need to be sure the coefficient of x^2 is 1, so divide all terms by 2:
x%5E2%2B4x=-5%2F2
Divide the coefficient of x by 2 and square the result. Add this to both sides of the equation in order to maintain the equality.
x%5E2%2B4x%2B4=-5%2F2%2B4
Simplify right hand side:
x%5E2%2B4x%2B4=3%2F2
Now, the left hand side can be written as a perfect square:
%28x%2B2%29%5E2=3%2F2
Take the square root of both sides:
x+2=+-sqrt(3/2)
Solve for x:
highlight%28x=-2%2B-sqrt%283%2F2%29%29
You can plug this into a calculator if you need a numerical answer, but this is usually good enough.
Good Luck,
tutor_paul@yahoo.com